1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for encoding a transport block.
2. Related Art
Extensive researches are underway in LTE (long term evolution) release 12 to improve performance in terms of capacity, coverage, coordination between cells, and costs. There is an ongoing discussion to introduce various techniques in the LTE release 12 in a technical aspect to improve performance, such as small cell enhancement, macro cell enhancement, new carrier type, machine type communication, etc.
The LTE release 12 aims at improving the capacity and coverage, which may be achieved by using small cell enhancement based on inter-site carrier aggregation, LTE-WLAN (wireless local area network) integration, and micro cell enhancement. Assuming a case where a cell is decreased in size, inter-cell movement of a terminal occurs frequently, which may result in an increase in an amount of traffic signaled when the terminal moves. To solve such a problem, a method of optimizing a small cell by decreasing signaling transmitted from an RAN (radio access network) to a core network on the basis of the small cell enhancement is under discussion in the LTE release 12.
In addition, an NCT (new carrier type) discussed in the LTE release 12 is a frame type which is newly defined differently from a legacy frame structure. Although the NCT can be a carrier type optimized for a small cell, it can also be applied to a macro cell. For example, in the NCT, an overhead generated by transmitting a reference signal such as a CRS (cell-specific reference signal) can be decreased, and a downlink control channel can be demodulated on the basis of a DM-RS (demodulation reference signal). By newly defining the NCT, energy of a base station can be saved, and an interference generated in a HetNet (heterogeneous network) can be decreased. In addition, the use of the NCT can decrease a reference signal overhead generated in data transmission using a plurality of downlink antennas. More specifically, although the legacy frame structure (e.g., a CP (cyclic prefix) length, a subframe structure, a duplexing mode, etc.) is maintained in the NCT, a control channel and/or a reference signal can be newly defined.